Abstract
Three rice lines were evaluated for vivipary, so called pre-harvest sprouting from the view point of dynamic states of water using nearly isogenic line. At 28 days-post anthesis (DPA) germination rate in NK2, as a pre-harvest resistant line, was similar to nk2, as a preharvest sesitive line, suggesting that there seems to be other genes controlling vivipary except for a single gene. At this stage both coleoptiles and radicles for NK2 and Taichung 65 (TC65) began to elongate, and the organs of TC65 were shortest among three lines. Therefore, it was indicated that rice seeds treated over 28 DPA easily lost their dormancy. The germination tests indicated that the genotypes did not differ in response to ABA in the mature seeds. In addition, there was no influence of ABA on water uptake into non-sprouting endosperms as well as sprouting endosperms of the three rice lines. ABA treatment decreased both T_2s of the both fractions in endosperms of the rice lines compared to those of DW treatment. These results suggested that the water bound with macromolecules appears to remain unchanged by ABA-treatment even in the sprouting phenomenon
